SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9a4a97da5acbfaf0398b13eae37b7e27c6bb2144ee1157b257336e1f772bb3b' 
  AND token = 'mXBE8Jv/Tx6Qp1fSP1vpx3DFZymxaY0PBJwaoNRGUeQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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