SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e80942a5381cddf94dcbb71224c195f97b147bfcc7e05447d228711471f36c7c' 
  AND token = 'sIPVEQDZ7Zw5P1z8q4Wahe5B8G4/YkdiVD3WZeP3GvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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