SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e774a8f464cad9452f2b41ad3d6736e4e5fedb0d12bf32e6d664f881a0fda074' 
  AND token = '3z1RafkQeDInvsvQoZ5HquOyg0r0OJJ4FlYzHCtZZrM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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