SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4477b8aa6cea021b9cb04e3923727440d612544533c2e798c81a48e69daf6343' 
  AND token = 'y1dHHUL2bRFW0mxLiOOzhoEFXhFKCmh3J/ulfu9EtnY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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