SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa46713eb40a56129b9943961cde35709257b1193dd185e734e9f683a8a9c3ac' 
  AND token = 'JL6dccuKiAnltfNQxDy9Di3NMS7NvUozssFYWnGN4WY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}