SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'feb4a14fb0b38c2576a87802d594c94d53f50d300b60bd21456f9b2103bd6140' 
  AND token = 'BqZgJ+dKTWCO6aeExpR1J1F/JgKqShkYKgZqDCxGhMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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