SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73143d65c99fb9678762dc52272aaa4ad1097d67eb55811bcfa852473295f1bb' 
  AND token = 'PLfxQHN3iNoJq7B87OUTNaoFfGqitYQpDDWItDoeczQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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