SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7bca14f9d331e2574c2477d5d1d34598dcad148b665b293ba5a95fc8b03183c9' 
  AND token = '78o/ZKGfGKw/6Wen0SPUkwyKsew4LqNjC1qRcTf9d/o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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