SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da2a34c8e91a239c0f0e7e68c3415c1d0681d3ef6743b682ee9f7b1cafa39ae8' 
  AND token = 'pqwjww7Gq0SRcbly9PGDyi24BpTWycDauPlJvNN7MxE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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