SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '748b05a079986079087ef2ab56bf4285b3ddea90e1757ca04bc5c2d888dba4ac' 
  AND token = 'CTtsOefudtpQA7XSwVeNx5VWUHTiXCigw6ij+OER5FE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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