SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96df538976061e77202528dc62e34568b3866c5d27c7a5ce5f8e8fe8836bf7f9' 
  AND token = 'i+GMdosRBo2vVstbGrVoB7NKYy5IUi1KKKEaojhOkAA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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