SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23f121e7cc41c0bd22936442f75311bf418d39634b9a245206a1638e0bc8ed07' 
  AND token = 'BKaYrAI0nA2vgFwOSJvE6ZckS4mZTbNXF6WfagrqaX4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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