SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f765ed13b92a99ef3009d6a1023a8d2af53b7d58ab538de3e49ff5e716beb0f8' 
  AND token = '5t6jDqeY6HvgI3T2ncX4CgmC4eWrzH/CsHUfxaWpoSo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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