SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6eff0612c7274e22d67052d59c7bc57f35aac12c86d2571eb9aa483000e72faf' 
  AND token = 'O7tbaVWLVWth9wLiZg3hirfiSC/hgbLvU7Ek0NClojc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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