SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba920647718bca0305ff81ed3909a95b7121d08a6bf5bdfe3064ec91876673cf' 
  AND token = 'Go0IJ4UUUuDnSOYgw/caJnZ2qcAmGVIzeqoGjTJfBr4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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