SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3455ab74a27221cccfb9160fc698ebf5ec971be28bdee09182481c6fdce2a93e' 
  AND token = '+LaKlieGDYwUghx9PLWGSLvPjlJ3xPpWgrNtZ8qqTrs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00011

JSON explain

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