SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '579091c88c014e4479c515b527487a2d145b5f88f9a8136e611d809e93483096' 
  AND token = 'q7kodgwNnTfYsmmethTO7VEag/gnby7IOjUfOW7OHYk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}