SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '075fdbdc7702254069bd90792a0206d391a839811d694352f72f18d7f028f147' 
  AND token = 'KhHCkeFo7JQXBxQgTDN7uryx2Zz3eNoOQJp8O3Gl3hQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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