SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d38ebbecd13a04cb8277e83181ace1e8cf968673d8bc346f94cd32a38484908' 
  AND token = 'W9SxbBmGLA6sYeT1mb01mOKFBEFV5SvZfcxFahjdFfU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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