SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8bc15d3af6e2ed4259e8e8f0872eb889c9dbaac998e75862e501c0d19f21a69c' 
  AND token = '3qoJxVVsouXGPwiVz9zP5vePscLk470l7oTo3kHj2e0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}