SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3abb100d554d9339d1a15a2c12a54948a65d9f7113d424dd2527c3346b1397be' 
  AND token = 'rZdSRjIktrEvikGIeSWKxEAv7laezbKMRjTjz/Kq90k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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