SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29a9fd2dbfa15f37be8aea7db80c6cd6ce07f54c1cf463188168cadcaab12fa3' 
  AND token = 'aNiYwBNVaZCaWwQTaBD25Ki4tRnwh1HeMLw+fL3pFbY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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