SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ff4f57cdb3b7cd9900ca95b0b7b5c4be771e8598f2dcbd550194a3aa87a8a266' 
  AND token = 'JQpOvQAuibAWgwQSojhm5gnXSgcIjAsn386WE1Q2EtU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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