SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a3ba00a1334bf4d92adab49d3ed8003fb058b0b4607951febf21068c785dbdd' 
  AND token = 'LHemdkNbGRhiMCWoBUSqdxYybSUIXvqgjAKbmIpkA4A=' 
  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"
    }
  }
}