SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88da45f2dd13e9bfea27a9038bf735938af21996e5e53dbe63dcfaec39876204' 
  AND token = 'VaocXKptQYTUkeZMyu1Gxp+lygfdkkDSiJ5d8eOnW7c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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