SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cded139c69feaf4cb30848fa83731231eb40fcd8faa2a3fbe298751f705a2d3f' 
  AND token = 'yUBiY2gSWDZInXJ7m+AQE1Kq+eGaJ3MGCG07DuM/zWw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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