SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '998a7c9f5589fa9c9dcd83f33d614cd6274ced32a426647e585674614154a1d0' 
  AND token = 'AggqGhPbGfvUH2cVCznZ6+hJa9kkdzuhuPJW9PGHkXc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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