SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31ec6692340c27a5b521f128df2b41f5a6458dfc12b0d85beb67c7fc0b9e215d' 
  AND token = 'W1qJI61EY/2mZ/mpNOfFFGPuIGx3/rB/rryzZVeZAg0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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