SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67c51075b6369de920c08cace4601d5e5d2245700c68ed086daed28566eb2533' 
  AND token = 'daZpIaBNVMDxFdIv1j2nO+k5wr7gm47OypvOPHh/rsA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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