SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc98baf3894da557d50e251c032be0921130f44cd23e51daf8ecfbb5252d10af' 
  AND token = '0KUeJkitibUHfPjuDAK6QP9SOKvcvaBAoFj/e8eIJUM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00123

JSON explain

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