SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40eaf5bce69a9483ffe37156bc3681e38cdf247ed4b436dce549d37ff789e210' 
  AND token = 'dSf7nDLxzxf0IsrV/3MldeWvCMRAJN3KZRbUJAuGMg4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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