SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2a4b2829dd0a0dfd8fdaf5203d373397b16839b21a121e18abfd695f0ba5c08' 
  AND token = 'w1HGKTJ7AQpEN4ChTqa8xXeoUdzZS3briqfAnUFEqYA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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