SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36c1b21052363358e0baa45a3f5a6619bb090fcb5b5efe037d36abef7ac4796c' 
  AND token = 'GSkBBFCGG4ukZwDVADTwAwafh/Hcwroky8knfMW3Gt8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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