SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '78cef0faab380594a564df7111cd307aac65a0e94e358711f28a90912660d355' 
  AND token = 'b//pu3OJBK8+l4paQshDx5yB7vAGGmu2fPHHCJqwfdY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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