SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9dcfc5237f6df8d4256ec695c575136452c179c777fe8a43b800154cee4b9cfc' 
  AND token = 'RG5J6ZteGBMtQVByzFiSMHpOK4b24LUZ1++x0vYYVpw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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