SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba75c72a3aff7273fba0da393e50c03994639e82574057fa61da69817521b368' 
  AND token = 'ungg9mu6SUUcBdK+I0snfKmv/Qb7fof4TXYVhkaiMEs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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