SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d4b1c2af173c873935d133dd97e7294f956ec2894762608bf90a715d7e52964' 
  AND token = 'HbMyN1XQ4M4mnjSXziOPmxukw6saHWr7cmu17k8NpnU=' 
  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"
    }
  }
}