SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e85e6e324f2a3900293b9f9702b95ebcd48b3afb507e308471cfaeed2b43f37d' 
  AND token = 'SguIQH31VIaALGmccYmIpsLB65jAJViv+rgMwZMTm/o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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