SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c017554d91ced86fbf60d25d1feee3697155a9179c6c6892322beff43af8ecfe' 
  AND token = '2ClZt9mMAb+PI+rDnLTAIkFMvraz0lDTlTmnbk9UXSU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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