SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34bdda98dea9d6edb17c39286a3818fc57194229e145852d1e5878d804ad4f03' 
  AND token = 'URJ/xAznAA9qePEyOZhcW69ce5/SQYsIDj7164vivHw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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