SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efbd5796318154dbb264d6d5e48f42a9ebcfff8b2a3539464d76895b368b4d18' 
  AND token = 'tBTLcO4M/YDRl85P5JDI1FslaTD6ivsuvY8c1N8aHtI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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