SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd68a6303374b32d7fb5f724406d7c6d366bc803b2ded9e83f9ba43bf1946709' 
  AND token = 'TrAPjtpJU4puBGNc0jcJLRV5YDNPxiZsvoFR+FmpD5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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