SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0958d375cb2d21c41102f7d0780aeb96a550a2c8407c348fcb9eee10b21a6fb' 
  AND token = 'pvB+HHUx6yMny/pNrQDHZCWZJS+Zi7IHDZjKhnfyoe0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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