SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c8ef4fceedac2a316afec3cdf87385d6a0bd411616570e3be80368722fe3269' 
  AND token = 'QBQD177cX+QeY4P/iO6vcyt5YbodmtYrYWKc1IgEeJg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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