SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '006576e68219f687e9aeefa4bf592377e608209599cf93953593a7e591902e87' 
  AND token = 'ZZlkfyPBY73+8EFvKQHpCS9CM3MbZMyAmIesCNaDEhY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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