SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cb7de8178bad2cf62195dd45658159d8f7f5f32fd434649be7e1a86917aad06' 
  AND token = 'g/v1u69jsKrjeFaBUHAKIPI0GDH+T5GXwakI+qeLk7M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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