SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4dc03c84097f7db2fb38b479371c30894fc1a2140f8d37f9c945890becc787c3' 
  AND token = 'PUiqiLMoavyCbBvNtIOng2MSxGqgA2k8yN+51teAVmg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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