SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5125fb3936bfd2b0a329dddb5efbc27f150d3589eeeb43adba52239008761c9b' 
  AND token = 'j2k3xd2yM+p4m1HvVphbhP/vrwY2MT4lix9rr92I47c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}