SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '519bd1851c5dff8373f4419520bbaf412fbeed71327e0ce4fec1809c6e171308' 
  AND token = 'eBKtxsPL25SYfCQYXKBw03cA2ieW5yMpF7yRKkUfjBY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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