SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e87527fe1ea01fcf6e7fe20eb287bb0959cef3d8416daa5e64788608c8e8927' 
  AND token = 'j5oUEIkerNVe988moG8Mmpi3LpRNHoOqbr3EaHryhCA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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