SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c129ef6086db85212154e5cd5f363b744a6da3e80711ce7ff9a80dbb81c91eb4' 
  AND token = 'AuZ/u1UnjRIqNnWxXXzgB8bivMUdcOoC/JHa15D5H60=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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