SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '070b41760b5349425ce9b2778d8b786ba712676a14bfc48051ee13df56f3a12c' 
  AND token = '4VpCA2TtmBOkvLqVw+MRDVBiYOLdK4n5K94bYYxhPZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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