SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '1a64c59b0a6920d36b8219b708e760783a91f9340f71dad81053f24d9e77bba2' 
  AND token = '8FyfRhwE+I5LFAg6ztPAks8yjreQV9UZDISL0Yj9GJc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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