SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '547d105237fa206fe5f27ff0c0ba1b09df6ddb15226540e01df319892020f279' 
  AND token = 'ad8xQAcaAhf40jqiEFtxxJQxzGYX7CKAJZ1BvrQnMgo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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