SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86757d90ff1de0acafbcae446a9d2fe477822568cdef93e757fb0e725b388407' 
  AND token = 'SDpShDEl+Sz3HbznJNzOmWQF/CprTIEnkLMllL+CF0I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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