SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d125f4b64f8153aa447c424f847de1f047b5f0d7b626e678d864825eb602446' 
  AND token = 'W3JTI5rIsVmNl65shB2hTiZLD4JRsmqlVwdpe7Yv/Oo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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