SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78ef10d6d7a2763a700c6ccf6473ab993268917c221d0af2298cfc92da4808b1' 
  AND token = '9T4urSK7B5dnXiWX1O6OO922Z4a46A3vZJsPyF2+Lbs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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