SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c97acb294afaa028429c8e137c0bd16b3d7383d0e9bb2335455bad62c78b6d9' 
  AND token = 'f3A+YCZRNcdjHNdQr6TTJwAHfepTJBpXH0yCCmjjFlk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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