SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4883a838123266e1bbfcdd864a025175f7bf4de072f33812fe8972bb03c0eed8' 
  AND token = 'ficE0dSQU5hgN3G7zh5BcTA3qSxIknsor5b73FNul48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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