SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8780562ba3a5d09c7cd8ef91331ecf9b426e96f50d3b80a6f473dfc3be2b356' 
  AND token = 'i6IQ4KzDqponIeqFO5b+DypLSawsPfLZMxqU56S1u1Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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