SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b4217f86116c3a19c3e6187ceb03f07f9dbfaee76986ff206e15d853f4ce6b6e' 
  AND token = '6oUDIaM8hiedu3YM9xrPVeo0N754gOciyHUSkOntmLU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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