SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '898cc1d65086d10e82339f7b213d931f249fa538e77a6fd55c9f944f37e4b50c' 
  AND token = 'T96ZS4HeEgKR5uHRyuEBYipmwEkFPAiJ0r59RrxdAkI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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