SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f8eb94c040b18a4d3999fd7a2fcafd2cb92ebecec32356426ef1339dea87656' 
  AND token = 'CGGYdwoTAsWgd7UBqNhYLIAYNiioSOpPpAXDPsY3paQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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