SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6dccd0ad2734584af93a16041c5eeae17bda8387445ab136007c5940f02d6b3f' 
  AND token = 'yTGhxnerFmWwG/jdFfqBIPGrpClbd1GA6pwBz91vMU4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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