SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e47d82a5b6ec7f68e0cd7c6014d0ead845d43957fdc8152d3e36d2b776653f0d' 
  AND token = 'WqRS7sgBZ4Wy5fp4IFmW9QaoE/HURvizLW8Lt0uQ8QA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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