SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c774bfca4dc42971dc7a001db0a77e19f6426f9f98ccac9b0ecd5a07d86bd316' 
  AND token = 'HPjMSuW5cLf/h0qHscdYPi6tZ9uxuojKp3RjNpCqhm4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}