SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f930a28e98d70a3b68eae5028fe436228de2bae46633b1865be56f0d9978733' 
  AND token = 'Q2IwwFv6YGjF2bWpSjOsDbL+RQhHfbHg4KV2WGhhrq4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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