SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f246452dccb5d68c5cd18356d0158cc03ca7b607b2653095974a4bcca88dab29' 
  AND token = 'GJnn4ROWTNKwv2LnaATTn1Wy2sxGckd25NBWHH7r/sg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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