SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '13e686c05851aecd15e6afaab74449862445e3e637b3b16e757acfda617f760a' 
  AND token = '4iRuUuceo8Kk112LV9yejllNLAdTeQMa9zCk8BG0Ias=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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