SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e55966dce27dd01f7a2f8fa90017f14be4be06aa1ffcc3c18d2ff77818d8d79' 
  AND token = 'c+MMiZLFCE6G7IrTE9lFTl/zycmZ3odPYjylecyDvFY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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