SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b16abc126bff4cdfcf004b2d5ae8063d9449d3ca7caccae7707ab33e2b92f799' 
  AND token = 'L16UMcyHI0nyVcJNJNjNTcWZOT3MPssfstt3vd772IA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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